Marinus Warmoeskerken

Laundry process intensification by ultrasound

In domestic textile laundering processes, mass transfer and mass transport are often rate limiting. Therefore, these processes require a long processing time, large amounts of water and chemicals, and they are energy consuming. In most of these processes, diffusion and convection in the inter-yarn and intra-yarn pores of the fabric are limiting mass transport mechanisms. Intensification of mass transport, preferentially in the intra-yarn pores, is the key in the improvement of the efficiency of wet textile processes. Conventional methods of intensification of mass transport (e.g. operation at elevated temperatures) are not always feasible due to the undesired side effects such as fabric damage. Increasing the flow rate does not deliver the desired effect due to the multi-porous complex structure of textile materials. Van der Donck et al. [Tenside Surf. Det. 35 (1998) 119; 36 (1999) 222] reported that the deformation of yarns by placing a fabric in a pulsating flow or repeated mechanical elongation of the yarns improved mass transport. However, the additional mass transport caused by deformation is limited in practice. Power ultrasound is a promising technique to accelerate mass transport in textile materials. Several papers appeared in this field, which report an improvement in energy efficiency and processing time of the wet textile processes in the presence of ultrasound. In this paper, the different time and length scales are discussed in the intensification of the mass transport in laundry processes in the presence of ultrasound and compared with more conventional processes. It has been concluded that the characteristic mass transport rates in textiles can be increased by a factor of 6 applying ultrasound.

Mechanism of interaction between cellulase action and applied shear force, an hypothesis.

An overview is given of what is known in literature concerning the structure of both cellulose and cellulase enzymes and the enzymatic degradation of cellulose. Based on this knowledge, a hypothesis is formulated about the relation between cellulase performance and required applied shear force on the fabric. In short, the specific cellulase activity is highest on the flexible amorphous cellulose when compared to that with the more rigid crystalline cellulose. When applying cellulase activity on damaged, fuzzy fabric, the connection point of cellulose material oriented away from the fiber axis, which is partly amorphous due to the damage, will be turned again to a more rigid, mainly crystalline structure. Due to this shift, this connection point will function as a primary point of application for shear force, resulting in removal of the fuzz.

A fast, continuous enzyme-based pretreatment process concept for cotton containing textiles

A fast integrated enzyme-based pretreatment process concept for cotton containing textiles has been developed for operation in the continuous mode. The total processing time for the desizing and scouring operation is 3–10 minutes for fabrics with a weight of 120–300 g/m2. Essential elements in the process are the high starting temperature, the presence of surfactant, application of vacuum technology and a robust rinsing process afterwards to remove the degraded pectin together with hydrophobic compounds. This rinsing procedure is realized with water containing chelator and surfactant and at high operation temperature beyond 80°C. A mixture of enzymes is used, consisting of a temperature stable α-amylase and a pectate lyase, both operating under alkaline conditions.

Guidelines to come to minimized tensile strength loss upon cellulase application

Application of cellulase technology in the textile production process often results in a certain loss of tensile strength along with the desired performance. In this paper guidelines are given how to come to minimization or even prevention of tensile strength loss. Part of the considerations is based on the hypothesis given in the accompanying paper (Lenting and Warmoeskerken, 2001, J. Biotechnol.) concerning the mechanism of interaction between cellulase action and applied shear force. Recommendations given concern the enzyme choice, process parameters and enzyme targeting.

Cutinase and pectinase in cotton bioscouring: an innovative and fast bioscouring process

This manuscript describes the potential of a cutinase from the fungus Fusarium solani pisi for cotton wax degradation in order to design an efficient low temperature scouring process. The main characteristics, relevant to cotton wax removal with F. solani pisi cutinase are given. The additive effect of cutinase on pectinase was investigated and optimum incubation conditions were determined. Compatibility of cutinase with surfactants, essential for the rapid migration of enzymes into the fabric, is explored. A clear strategy is presented to achieve a rapid enzymatic cotton scouring process. Wax removal with cutinase reduces pectinase incubation time and increases the hydrolytic rate of pectinase. Cutinase appears to be effective in the degradation of cotton waxes at low-temperature, allowing the design and introduction of a competitive innovative enzymatic scouring process.